$ { \left[\begin{array}{rr}{4} & {2} \\ {2} & {1} \\ {-1} & {4}\end{array}\right]-\left[\begin{array}{rr}{-2} & {0} \\ {-1} & {1} \\ {-2} & {4}\end{array}\right] = {?} } $
Solution: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{4}-{-2} & {2}-{0} \\ {2}-{-1} & {1}-{1} \\ {-1}-{-2} & {4}-{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{6} & {2} \\ {3} & {0} \\ {1} & {0}\end{array}\right]}$